Design: We conducted a randomized controlled trial (The Ageing and Dietary Intervention Trial) in 83 healthy volunteers aged 65–85 y with low FV intakes (#2 portions/d); 82 subjects completed the intervention. Participants were assigned to continue their normal diets or to consume $5 FV portions/d for 16 wk. At 12 wk, tetanus toxoid (0.5 mL intramuscular) and Pneumovax II vaccine
(0.5 mL intramuscular; both vaccines from Sanofi Pasteur) were administered.
FV intake was monitored by using diet histories, and biomarkers of nutritional status were assessed. The primary endpoint was the antibody response to vaccination. Specific antibodies binding to tetanus toxoid (total IgG) and pneumococcal capsular polysaccharide
(total IgG and IgG2) were assessed at baseline and 16 wk. Participants were recruited between October 2006 and June 2008